What is it?
Chiropractic is primarily the manipulation of bones in the spine in an effort to treat or prevent disease or to reduce discomfort. Though therapeutic manipulation of bones in the spine and elsewhere has a long history, chiropractic as it is understood today was invented in the late 19th century by Daniel David Palmer. He conceived the notion that all disease results from vertebrae in the spine being out of place (so-called “subluxations”), and that forcefully manipulation of the vertebrae (an “adjustment”) can prevent or treat disease. He gave varying explanations for this idea over time, often claiming that nerves carried a spiritual energy, called “innate intelligence,” and that obstruction of the flow of this energy by vertebral subluxations caused medical symptoms. There is no reliable evidence that vertebral subluxations as Palmer described them exist or cause disease, and even some chiropractors do not believe that subluxations are real or can be detected and treated by chiropractic methods.
Nevertheless, many chiropractors, especially those that still believe in Palmer’s subluxation theories, reject modern scientific explanations of illness. It is not unusual for these practitioners to deny that infectious organisms, such as bacteria and viruses, cause disease, and they frequently recommend avoiding accepted medical prevention or treatment, such as vaccination and antibiotic therapy.
Other chiropractors have rejected the subluxation idea and the claim that manipulation of the spine can prevent or treat disease in other parts of the body. These practitioners focus on the possible usefulness of chiropractic manipulation to treat back pain only, and often recommend both chiropractic and conventional medical therapy.
There is little consistency to the kind of therapy chiropractors provide. While most forcefully manipulate the spine, there are many different techniques and much controversy in the chiropractic literature about them. Chiropractors often utilize other treatment methods as well, applying heat, cold, laser light, magnets, electrical stimulation, and topical products to the patient, and recommending other alternative treatments such as herbal products. Overall, there is no universally accepted definition of what chiropractic is, what kinds of treatments it encompasses, or what conditions it might be useful for.
Chiropractic theory and practice has been applied to animals since Palmer’s time. Despite the dramatic and obvious differences between the anatomy of the human spine and that of all other mammals, chiropractors have often asserted that subluxations occur and cause disease in veterinary patients in the same way as in humans, and they have recommended therapeutic adjustment for animals. Even many chiropractors who do not believe in subluxation theory claim to be able to identify and treat back pain and other problems in animals.
Does It Work?
Despite decades of research and the use of imaging methods such as x-rays, CT scans, and MRI, no reliable evidence for the existence of Palmer’s vertebral subluxations has been found. Studies, even in journals devoted to chiropractic, have shown that common methods for detecting subluxations are unreliable. Individual chiropractors do not consistently identify the same sites for supposed subluxations in a given patient, nor can multiple chiropractors examining the same person agree on where the patient’s problem is located. Research studies show that the identification of a specific spot in the back as the source of a problem is essentially the same as picking a location at random.
Extensive research has been done on humans for use of chiropractic treatment in many different diseases. As always, the best quality scientific studies require blinding, where the patients and researchers do not know whether each subject is getting the real treatment or a fake (placebo) treatment, and this is difficult since a patient familiar with chiropractic may be able to tell which treatment they are getting, and it is impossible to blind the person giving the treatment. Many other factors complicate interpretation of human clinical trials, so confidence in the results can only come from consistent, repeatable outcomes of numerous well-designed trials conducted by different investigators.
When the best quality studies, with reasonable numbers of subjects and good controls for bias, are reviewed they find spinal manipulation to be ineffective for almost all conditions in which it has been tested. There is some reasonable evidence that spinal manipulation does can provide mild relief for back pain (an improvement of about 10 points on a 100 point pain scale). This level of relief is no greater than that provided by conventional medical therapy such as stretching, exercise, physical therapy, and non-steroidal anti-inflammatory drugs.
As is often the case with alternative therapies, there is no high-quality research on spinal manipulation or other chiropractic therapies in animals. Only small studies with poor controls for bias and lack of objective measures of outcome have been done. At this time, any claims for the usefulness of chiropractic treatment in animals are unfounded. Significant underlying anatomical differences between humans and other mammals suggest that therapy useful only for lower back pain in humans is unlikely to be relevant to disease in our four-legged veterinary patients.
Is it Safe?
Mild side-effects, such as headache, soreness, dizziness, and numbness occur in roughly half of human chiropractic patients. Much more rare, but also much more serious events have been reported. Tears in vertebral arteries can occur following manipulation of the neck, and these have led to stroke and permanent disability or death in a number of patients. Fractures of the vertebrae and rupture of intervertebral disks have also been reported.
Many chiropractors make extensive use of x-rays despite the lack of any evidence that such imaging methods can identify subluxations or other lesions amenable to chiropractic treatment. Though the danger of a single x-ray is minimal, repeated x-rays can increase cancer risk.
Those chiropractors who oppose conventional therapies and preventatives, such as antibiotics, pain medications, and vaccines, can be responsible for unnecessary risk and suffering in their patients by discouraging the use of proven, effective medical treatment or disease prevention. And as chiropractic therapy is not useful for problems unrelated to the spine, employing such treatment for other illnesses can delay appropriate diagnosis and treatment.
Finally, since the only demonstrated benefit of spinal manipulation is relief of back pain in humans, and since this therapy is no more effective than conventional medical therapy for these symptoms, the risks posed by chiropractic therapy seem unjustified by the benefits.
No reliable research exists on the safety of chiropractic treatment for veterinary patients. Injuries to horses from chiropractic manipulations have occasionally been reported. It is likely that the risk of vertebral artery tears would be lower given the differences in anatomy of the spine. However, it is also likely that the benefits for treatment of back pain in humans would not be relevant to veterinary patients for the same reason. And the use of chiropractic in place of legitimate scientific diagnosis and treatment would present the same risks for animals as for humans.
Ø There is no compelling evidence for the reality of Palmer’s concepts of innate intelligence or vertebral subluxations. Subluxations cannot be reliably identified, and even many chiropractors no longer believe they exist.
Ø The best quality clinical research shows that spinal manipulation provides no benefit for most conditions. It can provide mild relief of back pain in humans, at best equivalent to conventional medical therapy.
Ø There is no good-quality research to suggest spinal manipulation is of benefit in animals. Significant differences in the anatomy of the spine make it questionable whether veterinary patients would experience the same causes of lower back pain as humans or that manipulative therapy would provide the same benefits.
Ø There are several mild side effects commonly associated with chiropractic treatment in people, including headache, soreness, dizziness, and numbness. There are also rare but serious risks that can lead to disability or death in humans. No reliable research evidence exists regarding the safety of chiropractic treatment in animals.
References and More Information
Barker Bausell, R., Snake Oil Science: The Truth About Complementary and Alternative Medicine, Oxford University Press, 2007
Ernst, E., Canter, P.H., A systematic review of systematic reviews of spinal manipulation. J R Soc Med 2006;99:192-6
Hestboek, L., Leboeuf-Yde, C., Are Chiropractic Tests for the Lumbo-Pelvic Spine Reliable and Valid? A Systematic Critical Literature Review. J Manip Physiolog Therap May 2000;23(4)
International Chiropractic Pediatric Association, Vaccine Information Website, http://www.icpa4kids.org/research/children/vac_info.htm
Leon-Sanchez, A., Cuetter, A., Ferrer, G., Cervical spine manipulation: an alternative medical procedure with potentially fatal complications. South Med J Feb 2007;100(2):201-3
Ramey, D., Rollin, B., Complementary and Alternative Veterinary Medicine Considered, Iowa State Press, 2004
Sing, S., Ernst, E., Trick or Treatment: The Undeniable Facts About Alternative Medicine, W.W. Norton & Company, 2008
Stevinson, C., Ernst, E., Risks associated with spinal manipulation. Am J Med May 2002;112(7):566-71
Vohra, S., et al., Adverse events associated with pediatric spinal manipulation: a systematic review. Pediatrics Jan 2007;119(1):275-83.
The Cochrane Collaboration, The Cochrane Reviews, a searchable database of systematic reviews of the human medical literature at http://www.cochrane.org/reviews/
© Brennen McKenzie, 2008
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